Correspondence ICS-INQUA on definition and status of the Quaternary / Pleistocene

ICS-INQUA joint ‘task force’ working group on the Quaternary


For over a century, the status and stratigraphic position of the Quaternary have been debated. Authoritative papers on the history of Quaternary, and its recommended stratigraphic definition and status include Berggren (1998), Lourens et al. (2004), Ogg (2004), Pillans (2004) and Gibbard et al. (2005). The INQUA Executive, through consultation with the Quaternary community in 2004, has found widespread support for defining the Quaternary as a chronostratigraphic unit with a base at 2.6 Ma. As a consequence, ICS and INQUA consider it timely to decide on the stratigraphic meaning of the Quaternary, so that it can be unequivocally placed in the standard global time scale. John Clague, President of INQUA, Felix Gradstein, Chair of ICS, assisted by outgoing IUGS President Ed de Mulder, have agreed that a task force be formed that will make a recommendation to ICS and INQUA on the definition of the Quaternary in 2005.

‘Task force’ working group

The task force on the Quaternary will comprise members of INQUA and ICS, and will be charged with the single task of defining the Quaternary in a stratigraphic sense. It will formulate a single proposal that will be discussed at the Second ICS Workshop on the Future of Stratigraphy in September 2005 in Leuven, Belgium (see below). This workshop will be attended by the chairs of all Subcommissions of ICS, and the President of the INQUA Commission on Stratigraphy and Geochronology. If the task force recommends definition in a formal chronostratigraphic sense, its proposal will go through the standard ICS consultation, voting, and ratification procedures.

The task force consists of 9 members and will receive advice and input from its wider constituency. The members of the task force are:

Chair: James Gehling, Australia (
Vice-Chair: Brad Pillans, Australia (
Secretary: James Ogg, USA (

Nicholas Shackleton (
Jan Piotrowski (,
Leszek Marks (
John van Couvering (
Phil Gibbard (
Frits Hilgen (

*see voting results below.


Berggren, 1989. The Cenozoic Era: Lyellian (chrono) stratigraphy and nomenclatural reform at the millennium. In: Blundell, D.J. & Scott, A.C. (eds) Lyell: the past is the key to the Present. Geological Society, London, Special Publication 143, 11-132.
Gibbard, P.L., Smith, A.G., Zalasiewicz, J.A., Barry, T.L., Cantrill, D., Coe, A.L., Cope, J.C.W., Gale, A.S., Gregory, F.J., Powell, J.H., Rawson, P.F., Stone, P. & Waters, C.N. 2005 What status for the Quaternary? Boreas, 34, 1- 6.
Lourens, L., F. Hilgen, N.J. Shackleton, J. Laskar and D. Wilson, 2004. The Neogene Period. In: Gradstein, Ogg and Smith, 2005. Geologic Time Scale 2004. Cambridge University Press.
Ogg, J., 2004. Introduction to concepts and proposed standardization of the term Quaternary. Episodes 27 (2), 125-126.
Pillans, B., 2004. Proposal to redefine the Quaternary. Episodes 27 (2), 127.
Cita, M.B. 2004 ISSC Newsletter No.6.

This working group reported to the ICS meeting held in Leuven in Belgium in September 2005.

**Depositions to this group are welcome and should be made to the Secretary James Ogg ( and copied to Phil Gibbard ( and Brad Pillans (

Further details on the ‘task force’ working group

Papers for reference purposes concerning definition
Hörnes, M. 1853 Mittheilung an Professor Bronn gerichtet, Wien”, Neu. Jb. Min. Geol. Geog. u. Petrefakt., 806-810.
Partsch, P. & Hörnes, M. 1856 Die Fossil Mollusken des Tertiaer-Beckens von Wein. Fol.; Nr. I, Tf. 1-5, 1-42.

Report of informal Cambridge meeting 24 March 2005

A special meeting was held in the Department of Geography, University of Cambridge on 24 March 2005 to discuss the definition and recognition of the Quaternary and its boundary with the Neogene (Tertiary).

The meeting was attended by 10 people, including: John van Couvering, Charles Turner, Nick Shackleton, Alan Smith, Stijn de Schepper, Maria Papanikolaou, Martin Head, Leszek Marks, Jan Piotrowski and Phil Gibbard. This position paper presents the strong recommendations of this group and represents a virtually unanimously agreed statement on the status of the term ‘Quaternary’. The task force was due to report to the ICS meeting in Leuven in September 2005, but had at that time taken no action. It was decided therefore to organise a discussion meeting with an international group of Quaternary scientists, including both marine and continental workers. This group met to discuss matters and to draw up a paper which could be put before the ‘task force’ to assist it with its’ deliberations.

The meeting was held in response to the present discussions about (a) the status of the Quaternary, and (b) consequently the nature and position of the Neogene/Quaternary (N/Q) boundary (if any). It is also naturally related to other discussions which concern the Pliocene-Pleistocene (P-P) boundary.

 Download the full text (2 pages)

Results of votes by the ‘task force’ working group on the Quaternary 2005

The results of the ballots of members of the working group on the definition of the Quaternary, collated by J.Ogg the Secretary of the ICS and the ‘task force’ group, can be downloaded here.

Message addressed to ICS chairs (26.8.05):

The topic for discussion in Leuven is a formalization of the term Quaternary, and a possible placement within the international geologic time scale. The Quaternary Task Group report (below) is the result of a joint team assigned by INQUA (International Union of Quaternary Research) and ICS.

In 1985, with the placement of the base-Pleistocene GSSP, “The subject of defining the boundary between the Pliocene and Pleistocene was isolated from other more or less related problems, such as the pending definition of the Calabrian, and the status of the Quaternary within the chronostratigraphic scale.” — E. Aguirre and G. Pasini (1985, The Pliocene-Pleistocene Boundary. Episodes 8: 116-120. = official publication of the base-Pleistocene GSSP decision by the special joint INQUA-ICS working group).

For various reasons, partially summarized in the attached report and its appendices, the “pending definition … and status of the Quaternary” was never resolved and submitted to ICS/IUGS for consideration or ratification. As a result, the INQUA and Quaternary workers are commonly using one definition (based on Earth’s major environmental changes), whereas several published time scales have implied another definition (and display an unratified placement on the geologic time scale).

In Leuven, the discussions and recommendations of the joint INQUA-ICS task group will be summarized, then we will consider their proposals.

Jim Ogg (Secretary, ICS)

Results of the INQUA poll on the definition of the Quaternary 2006

The INQUA Executive Committee polled its constituents on the status of the ‘Quaternary.’ The Executive Committee asked individuals and INQUA National Committees whether the recommendation of the International Commission on Stratigraphy (ICS), based on discussions at Leuven in the autumn of 2005, was acceptable or unacceptable (request below). That recommendation was that the Quaternary be assigned the status of a Sub-Era/Sub-Erathem with its base at the base of the Pliocene Gelasian Stage GSSP at ca. 2.6 Ma at Marine Isotope Stage 103. INQUA received 204 responses, of which 188 were from individual scientists and 16 were from INQUA National Committees. Verbatim responses are provided in the file below and are summarized in the formal letter to the chairman of ICS (below). They can be downloaded here.

ISQS is grateful to the INQUA Executive, and especially the President (J.Clague) and the Secretary (Peter Coxon), for permission to reproduce these letters.

ICS response to the formal position of INQUA – August 2006

Following the poll on the definition of the Quaternary by INQUA the ICS has sent a response on 19.8.06, which can be downloaded here.

ICS response to INQUA on the status and definition of the Quaternary (and the base of the Pleistocene).

INQUA response to ICS – November 2006

The INQUA response by the President J.Clague 26.11.06 to the ICS letter from F.Gradstein can be downloaded here.

INQUA response to ICS on the status and definition of the Quaternary (and the base of the Pleistocene).

ICS response to the formal position of INQUA – December 2006

The ICS reply sent on 18.12.06, which can be downloaded here.

ICS response to INQUA on the status and definition of the Quaternary (and the base of the Pleistocene) dated 18.12.06

IUGS letter to Subcommission chairs and others – February 2007

A letter dated 5.2.07, reprimanding the ICS Executive over their inaction on a range of topics, including in particular their handling of the Quaternary issue, can be downloaded here.

The letter from the IUGS President Zhang Hongren to ICS Subcommission chairs.

Request for discussion on whether to forward INQUA’s position on Quaternary directly to IUGS for possible acceptance

the formal response of Subcommission on Neogene Stratigraphy to the request from ICS for discussion on the Quaternary ballot. From Frits Hilgen, SNS chair

ICS VOTE on QUATERNARY and move of Pleistocene boundary to 2.6 Ma – 14.4.07. – [chart]

Results of the ICS vote on the STATUS AND DEFINITION OF QUATERNARY and the base of the PLEISTOCENE published 14.5.07

IUGS decision on Quaternary definition 28.05.07

‘Fresh Start’ – new negotiations begin between INQUA + ICS on the classification of the Quaternary and its relation to Tertiary, Neogene, etc. – to be discussed at the International Geological Congress in Oslo, August 2008.